Flupirtine(D 9998) is a selective neuronal potassium channel opener that also has NMDA receptor antagonist properties.;IC50 Value: ;Target: Potassium channel; NMDA receptor;In vitro: High concentrations of flupirtine antagonized inward currents to NMDA(200 microM) at -70 mV with an lC50 against steady-state responses of 182.1+/-12.1 microM. The effects of flupirtine were voltage-independent and not associated with receptor desensitization making actions within the NMDA receptor channel or at the glycine modulatory site unlikely. NMDA receptor antagonism probably has little relevance for the clinical efficacy of flupirtine as the concentrations needed were far higher than those achieved in clinical practice. However, the activation of a G-protein-regulated inwardly rectifying K+ channel was identified as an interesting molecular target site of flupirtine. In the next stage, the central nervous spectrum of action of experimental K+ channel openers (PCO) was considered. As far as they MedChem ExpressHY-17001A